In the formation of color paper it is known that the base paper has applied thereto a layer of polymer, typically polyethylene. This, layer serves to provide waterproofing to the paper, as well as providing a smooth surface on which the photosensitive layers are formed. The formation of a suitably smooth surface is difficult, requiring great care and expense to ensure proper laydown and cooling of the polyethylene layers. The formation of a suitably smooth surface would also improve image quality, as the display material would have more apparent blackness as the reflective properties of the improved base are more specular than the prior materials. As the whites are whiter and the blacks are blacker, there is more range in between and, therefore, contrast is enhanced. It would be desirable if a more reliable and improved surface could be formed at less expense.
Prior art photographic reflective papers comprise a melt extruded polyethylene layer which also serves as a carrier layer for optical brightener and other whitener materials, as well as tint materials. It would be desirable if the optical brightener, whitener materials, and tints, rather than being dispersed in a single melt extruded layer of polyethylene, could be concentrated nearer the surface where they would be more effective optically.
Prior art photographic reflective materials typically contain cellulose fiber paper to provide support for the imaging layers. While paper is an acceptable support for the imaging layers, providing a perceptually preferred feel and look to the photograph, paper does present a number of manufacturing problems which reduce the efficiency at which photographic paper can be manufactured. Problems include those such as processing chemistry penetration into the edges of the paper, paper dust as photographic paper is slit, punched and chopped, and as loss of emulsion hardening efficiency because of the moisture gradient that exists between the photographic emulsion and the paper. It would be desirable if a reflective image could be formed without the use of cellulose paper.
Prior art photographic bases are also know to contain oriented white reflective films that are adhesively adhered to a base substrate such as paper or plastic such as polyester. Such bases are coated with light sensitive silver halide photographic layers or with image receiving layers such as inkjet, thermal dye transfer and others. Typical imaging supports are disclosed in U.S. Pat. Nos. 5,866,282; 5,853,965; 5,888,681; 5,998,119; 6,043,009 and 6,218.059.
In reflective photographic papers there is a need to protect the imaging layers from scratches, fingerprints, and stains. Current photographic reflective papers use a gelatin overcoat to protect the imaging layers. While the gelatin does provide some level of protection, it can easily be scratched reducing the quality of the image. Further, fingerprints or stains caused by common household liquids such as coffee, water, or fruit juice can easily stain and distort images. Wiping the images while wet causes undesirable distortion to the gelatin overcoat. Post photographic processing equipment exists that provides a protective coating to the imaging layers. Typically consumer images are individually coated or laminated with a polymer to provide protection to the image layers. A common example is photographic identification badges that are typically laminated with a clear polymer sheet to provide protection to the image on the identification badge. Post processing application of a protective layer is expensive, as it requires an additional step in the preparation of the reflective print and additional materials to provide the overcoat. It would be desirable if a reflective photographic image could be formed with a protective coating over the developed image layers that could be efficiently applied.
Typically, photographic reflective imaging layers are coated on a polyethylene coated cellulose paper. While polyethylene coated cellulose paper does provide an acceptable support for the imaging layers, there is a need for alternate support materials such as polyester or fabric. The problem with alternate, non-paper supports is the lack of robustness in photographic processing equipment to mechanical property changes in supports. The photographic processing equipment will not run photographic materials that have significantly different mechanical properties than prior art photographic materials. It would be desirable if a reflective photographic image could be efficiently formed on alternate supports.